[meteorite-list] New Observations Slightly Decrease Mars Impact Probability (Asteroid 2007 WD5)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 2 Jan 2008 18:42:11 -0800 (PST)
Message-ID: <200801030242.SAA19578_at_zagami.jpl.nasa.gov>

http://neo.jpl.nasa.gov/news/news154.html

New Observations Slightly Decrease Mars Impact Probability
Don Yeomans, Paul Chodas and Steve Chesley
NASA/JPL Near-Earth Object Program Office
January 2, 2008

Additional position observations for asteroid 2007 WD5 taken on December
29 through January 2 have been used to improve the accuracy of the
asteroid's orbit. As a result, the range of possible paths past Mars has
narrowed by a factor of 3 and the most likely path has moved a little
farther away from the planet, causing the Mars impact probability to
decrease slightly to 3.6% (about one chance in 28). The new positional
observations were made using the 2.4 meter telescope at New Mexico
Tech's Magdalena Ridge Observatory and reported by astronomer Bill Ryan.
It seems likely that as additional observations further shrink the
uncertainty region of this asteroid, the region will no longer intersect
Mars and the impact probability will quickly drop to zero.

[Graphic]
Updated Uncertainty Region for 2007 WD5 at encounter with Mars, shown as
white dots. The thin white line is the orbit of Mars. The blue line
traces the motion of the center of the uncertainty region, which is the
most likely position of the asteroid. Note that the scale is
considerably finer than it has been in past diagrams
Received on Wed 02 Jan 2008 09:42:11 PM PST